问题 问答题 简答题

棒型浮选机的工作原理是什么?其有何优点?

答案

参考答案:

靠斜棒叶轮的旋转与凸台之间所产生的负压,空气经竖轴吸入并被分割弥散成气泡。叶轮搅拌与抛射矿浆,在凸台和四周弯曲程度不同的稳流板的导向作用下,使气泡与矿浆充分混合,由台底各部位折向液面徐徐上升。矿化气泡升浮至泡沫区刮出。矿浆自流至下一台中。

其优点为:结构简单,吸气量大,搅拌力强,能处理较粗的矿砂,降低电耗。

问答题
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     A well-dressed man entered a famous jewelry shop. He explained he wished to buy a pearl for his

wife's birthday and the price didn't matter since business had been very good for him that year. After

examining a nice black one that cost $5000, he paid for it in cash, shook hands with the jeweler, and left.

     A few days later the man returned and said that his wife liked the pearl so much that she wanted another one just like it. It had to be exactly the same size and quality, as she wanted a pair of earrings made,

"Can you give me any advice on how to get such a pearl?" said the man. The jeweler regretfully replied,

"I would say it's exactly impossible to find one exactly like that pearl."

     The rich man insisted that the jeweler advertise in the newspapers, offering $ 25,000 for the matching

pearl. Many people answered the advertisement but nobody had a pearl that was just right.

     Just when the jeweler had given up hope, a little old lady came into his store. To his great surprise, she pulled the perfect pearl from her purse. "I don't like to part with it," she said sadly, "I inherited it from my

mother, and my mother inherited it from hers. But I really need the money."

     The jeweler was quick to pay her before she changed her mind. Then he called the rich man's hotel to

tell him the good news. The man, however, was nowhere to be found.

1. The man paid $ 5,000 for the black pearl without bargaining because ______.

A. he wanted to make the jeweler believe him      

B. his business had been successful

C. he was anxious to get it      

D. he was very rich

2. He told the jeweler to get him another pearl that must be ______.

A. exactly the same size as the black one

B. exactly as big and nice as the black one

C. worth no more than $ 25,000

D. exactly the same quality as the black one

3. Many people answered the advertisement because they wanted _______.

A. to see the perfect pearl

B. to buy some beautiful pearls too

C. to get in touch with the rich man

D. to sell their own pearl at a high price

4. The jeweler couldn't find the man anywhere because ______.

A. he died suddenly.

B. He happened to be out

C. He got $ 20,000 by cheating and had run away with the money.

D. He wouldn't show up until the jeweler called him a second time.